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Periodic Table of Elements

Element Potassium - K

Comprehensive data on the chemical element Potassium is provided on this page; including scores of properties, element names in many languages, most known nuclides of Potassium. Common chemical compounds are also provided for many elements. In addition technical terms are linked to their definitions and the menu contains links to related articles that are a great aid in one's studies.

Potassium Menu

• Potassium Page One
  • Overview of Potassium
  • Potassium's Name in Other Languages
  • Atomic Structure of Potassium
  • Chemical Properties of Potassium
  • Physical Properties of Potassium
  • Regulatory / Health
  • Who/When/Where/How
• Potassium Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides
• Potassium Page Three
  • Common Chemical Compounds of Potassium

Overview of Potassium

• Atomic Number: 19
• Group: 1
• Period: 4
• Series: Alkali Metals

Potassium's Name in Other Languages

• Latin: Kalium
• Czech: Draslík
• Croatian: Kalij
• French: Potassium
• German: Kalium - s
• Italian: Potassio
• Norwegian: Kalium
• Portuguese: Potássio
• Russian: Калий
• Spanish: Potasio
• Swedish: Kalium

Atomic Structure of Potassium

• Atomic Radius: 2.77Å
• Atomic Volume: 45.46cm³/mol
• Covalent Radius: 2.03Å
• Cross Section (Thermal Neutron Capture) σ_a/barns: 2.1
• Crystal Structure: Cubic body centered

  

• Electron Configuration:

  1s² 2s²p⁶ 3s²p⁶ 4s¹

• Electrons per Energy Level: 2,8,8,1

  Shell Model
  

• Ionic Radius: 1.38Å
• Filling Orbital: 4s¹
• Number of Electrons (with no charge): 19
• Number of Neutrons (most common/stable nuclide): 20
• Number of Protons: 19
• Oxidation States: 1
• Valence Electrons: 4s¹

  Electron Dot Model
  

Chemical Properties of Potassium

• Electrochemical Equivalent: 1.4587g/amp-hr
• Electron Work Function: 2.3eV
• Electronegativity: 0.82 (Pauling); 0.91 (Allrod Rochow)
• Heat of Fusion: 2.334kJ/mol
• Incompatibilities:

• Ionization Potential
  • First: 4.341
  • Second: 31.625
  • Third: 45.72
• Valence Electron Potential (-eV): 10.4

Physical Properties of Potassium

• Atomic Mass Average: 39.0983
• Boiling Point: 1032K 759°C 1398°F
• Coefficient of lineal thermal expansion/K^-1: 83E^-6
• Conductivity

  Electrical: 0.139 10⁶/cm Ω
  Thermal: 1.024 W/cmK

• Density: 0.862g/cc @ 300K
• Description:

  Very soft silvery metal that quickly oxidizes to white in air and reacts violently in water.

• Elastic Modulus:
  • Bulk: 3.1/GPa
  • Rigidity: 1.3/GPa
  • Youngs: 3.53/GPa
• Enthalpy of Atomization: 89.5 kJ/mole @ 25°C
• Enthalpy of Fusion: 2.32 kJ/mole
• Enthalpy of Vaporization: 77.5 kJ/mole
• Flammablity Class:
• Freezing Point: see melting point
• Hardness Scale
  • Brinell: 0.363 MN m^-2
  • Mohs: 0.4
• Heat of Vaporization: 79.87kJ/mol
• Melting Point: 336.5K 63.35°C 146.03°F
• Molar Volume: 45.46 cm³/mole
• Physical State (at 20°C & 1atm): Solid
• Specific Heat: 0.75J/gK
• Vapor Pressure = 0.000106Pa@63.35°C

Regulatory / Health

• CAS Number
  • 7440-09-7
• RTECS: TS6465000
• OSHA Permissible Exposure Limit (PEL)
  • No limits set by OSHA
• OSHA PEL Vacated 1989
  • No limits set by OSHA
• NIOSH Recommended Exposure Limit (REL)
  • No limits set by NIOSH
• Levels In Humans:
  Note: this data represents naturally occuring levels of elements in the typical human, it DOES NOT represent recommended daily allowances.
  • Blood/mg dm^-3: 1620
  • Bone/p.p.m: 2100
  • Liver/p.p.m: 16000
  • Muscle/p.p.m: 16000
  • Daily Dietary Intake: 1400-7400 mg
  • Total Mass In Avg. 70kg human: 140 g

Who / Where / When / How

• Discoverer: Sir Humphrey Davy
• Discovery Location: London England
• Discovery Year: 1807
• Name Origin:

  From potash (pot ash); K from latin: kalium

• Abundance of Potassium:
  • Earth's Crust/p.p.m.: 21000
  • Seawater/p.p.m.: N/A
  • Atmosphere/p.p.m.: N/A
  • Sun (Relative to H=1E¹²): 145000
• Sources of Potassium:

  Found in minerals like carnallite [(KMgCl₃).6H₂O], sylvite (KCL) and alunite. Annual world production is around 200 tons. Primary mining areas are in Germany, Spain, Canada, USA and Italy.

• Uses of Potassium:

  Used as potash in making glass, soap, lenses and salt substitute. Also as saltpeter, potassium nitrate (KNO₃) it is used to make explosives and to color fireworks in mauve.

• Additional Notes:

  Formerly called kalium hence the symbol 'K'.

Potassium Menu

• Potassium Page One
  • Overview of Potassium
  • Potassium's Name in Other Languages
  • Atomic Structure of Potassium
  • Chemical Properties of Potassium
  • Physical Properties of Potassium
  • Regulatory / Health
  • Who/When/Where/How
• Potassium Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides
• Potassium Page Three
  • Common Chemical Compounds of Potassium

References

A list of reference sources used to compile the data provided on our periodic table of elements can be found on the main periodic table page.

Related Resources

• Anatomy of the Atom
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• Molarity, Molality and Normality
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• Molar Mass Calculations and Javascript Calculator
  Molar mass calculations are explained and there is a JavaScript calculator to aid calculations.
• Chemical Database
  This database focuses on the most common chemical compounds used in the home and industry.

Citing this page

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Kenneth Barbalace. Periodic Table of Elements - Potassium - K. EnvironmentalChemistry.com. 1995 - 2024. Accessed on-line: 12/21/2024
https://EnvironmentalChemistry.com/yogi/periodic/K.html
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